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Additional removal of phosphorus using coagulant by purification of wastewater in sand filters Texto completo
2011
Gasiunas, V., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst. | Askinis, S., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst.
The aim of the study was to examine the effect of coagulant PAX – 18 (polyaluminum chloride) on additional phosphorus removal in reed sand filters. Batch experiments for precipitation reaction with wastewater from septic tank and after treatment in the reed sand filter were carried out. The doses of coagulant under 200 mg L-E1 and time of coagulation under 72 h were applied. Coagulant PAX – 18 efficiently removes phosphorus from the wastewater. The efficacy of removal depends on the dose of coagulant and the time of coagulation. Optimal hydraulic retention time is about 40 hours. With regard to the consumption of coagulant to remove 1 mg of P, it is most efficient to apply coagulant before wastewater treatment in the filter. During the coagulation time of 40 hours, 1 milligram of aluminium oxide precipitated 0.23 mg of P in the wastewater from the filter and 0.39 mg in the wastewater from the septic tank. In this case the removal of P was 1.65 times more effective. Coagulant decreases the wastewater pollution according to BOD5 and the concentration of suspended solids. Therefore, it is advisable to use the coagulant before wastewater treatment in the filter, as it reduces the organic load of filters and the possibility of filter clogging due to lower concentration of suspended solids.
Mostrar más [+] Menos [-]Removal of the organic pollution from the dairy wastewater of the milk collection station in the differently constructed sand filters Texto completo
2011
Askinis, S., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst.
In 2003 an experimental model of the dairy waste water cleaning facility was equipped for cleaning the wastewater of the milk collection station. We examined the possibilities to destruct the organic pollutants present in the dairy wastewater in the sand filters of vertical and horizontal filtration. The pollution level of the dairy wastewater is from 2 to 4 times higher than that of the domestic wastewater. The dairy wastewater was cleaned following the procedure: cleaning in the aeration-flocculation system-cesspool-two stage sand-reed filter. The pollution of the wastewater leaving the cleaning facility never exceeded the allowable norms. The average BOD5 was 4 mg O2 LE-1 and the maximal value was 9.6 mg O2 LE-1. The investigation revealed that the horizontal sand-reed filter with the filtration path of 7 meters ensured cleaning of the dairy wastewater up to the allowable norms. The organic pollutants were cleaned with the efficiency of 97.2% after filtration through such a sand layer. In order to find out the possibilities of vertical filtration filters use for cleaning the dairy wastewater leaving the milk collection stations, we performed a modelled investigation. The wastewater cleaning efficiency in respect to BOD5 reaches 99.3% in these filters. The calculation according to the regression equation received showed that filtration through 0.6 m sand layer ensured successful cleaning of the wastewater up to the allowable norms. In such a vertical filtration filter the average BOD5 cleaning level was 20 mg O2 LE-1.
Mostrar más [+] Menos [-]Influence of the vertical filter media on phosphorus removal from the domestic wastewater Texto completo
2011
Kazakeviciene, J., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst. | Askinis, S., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst.
Modelling of the domestic wastewater treatment and removal of the Ptotal in the vertical filters with the sand, dolomite powder and dolomite chippings each separately used as a filter media was performed. Six filter models taking 0.2 m2 each were installed. The length of the filtration path was equal to 0.8 m in three of these models and 0.4 m in the other three models. The hydraulic load on the filters was equal to 0.03 m3 mE-2 dE-1 in 2008, and it was equal to 0.06 m3 mE-2 dE-1 in 2009. The domestic wastewater which had undergone the pre-cleaning in the septic systems was poured into the models. Their average pollution with the Ptotal reached 14.6 mg LE-1 in the first year and 9.2 mg LE-1 in the second year. When the filtration path was equal to 0.8 m and the hydraulic load was equal to 0.03 m3 mE-2 dE-1, the Ptotal was removed from the wastewater with the efficiency of 99.9% in the dolomite powder filter. In the filter models with the sand and dolomite chippings, the Ptotal was removed with the same efficiency of 87.7%. When the hydraulic load doubled, the efficiency of P removal decreased to 59.8% in the sand filter and down to 45.7% in the dolomite chippings filter. When the hydraulic load reached 0.06 m3 mE-2 dE-1, only the dolomite powder filter could ensure the adequate cleaning of the domestic wastewater up to the allowable norms.
Mostrar más [+] Menos [-]Principles for planning residential area greenery Texto completo
2011
Ile, U., Latvia Univ. of Agriculture, Jelgava (Latvia)
The article presents information on the greenery in the large-scale residential area courtyards built in the Soviet period. The data on the importance of the greenery in the large-scale residential areas of the Baltic States were analysed. The analysis was carried out on the large-scale residential area courtyards built in the second half of the 20th century in Pärnu, Jelgava, and Siauliai, which until present have not experienced any changes of the landscape. The research established that these courtyards can be characterised as the unused territory resources. Consequently, there is a necessity to resolve the topical issues of the greenery in the Soviet period large-scale residential area courtyards. From the theoretical aspect, the information gathered in the research on the greenery in the large-scale residential areas has revealed relevant suggestions for the improvement of the present condition. The variety of information reflects the significance of the greenery in the large-scale residential area courtyards that have to provide an aesthetically pleasant image of the territory for every inhabitant of the territory. The methods applied in the research describe the present condition of the Soviet period courtyards.
Mostrar más [+] Menos [-]The historical development of watermills and small-scale hydroelectric power plants landscape in Latvia Texto completo
2011
Lazdane, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
The change in landscape is a never-ending process. In this article information regarding watermills and small-scale hydroelectric power plants historical development in Latvia has been summarized. The research was conducted from September 2010 till April 2011 with the aim of summarizing information regarding impacts to landscape from changes occurring from 12th century till 21st century. The research had a detailed view about the usage history of the watermills, small-scale hydroelectric power plants buildings, and energy producing constructions. The fundamental changes in energy producing mechanisms and legislation regulations changes that have an impact on river open space landscape and on landscape use in surrounded territories of watermills and small-scale hydroelectric power plants landscape were analyzed and studied carefully. The territories were described and analysed using historical, monographic, and comparative methods. The paper gives possible descriptive historical classification of these industrial landscape elements. The historical progress and legislation evolution until the 21st century has also been summarized.
Mostrar más [+] Menos [-]The estimation of the emission of greenhouse gasses by the treatment of sewage sludge in Latvia Texto completo
2011
Arina, D., Latvia Univ. of Agriculture, Jelgava (Latvia);Institute of Physical Energetics, Riga (Latvia) | Bendere, R., Institute of Physical Energetics, Riga (Latvia)
The report presents the assessment of emission of greenhouse gases (GHG) generated by the treatment, disposal and storage of sewage sludge in Latvia. The aim of the study was to determine GHG emissions from stored sludge because those were not previously estimated. The proposals for the further reduction of the GHG emissions are elaborated on the provided estimations of different treatment models. The calculations of GHG emissions are conducted by using acknowledged software and data from Latvian Environment, Geology and Meteorology Centre. Data from the year 2005 till 2009 about the amount of stored sludge were used by the authors for mathematical calculations in the year 2010. The long-term storage of sewage sludge and their disposal in landfills were detected as the main sources of GHG. It was detected that the average GHG reduction of 5 Gg per year can be ensured by using biological treatment of sewage sludge.
Mostrar más [+] Menos [-]Growth and reproductive performance of Fogera cattle breed at Andassa Livestock Research Center Texto completo
2016
Tesfa, A. | Kumar, D. | Abegaz, Solomon | Mekuriaw, Getinet | Bimerew, T. | Kebede, A. | Bitew, A. | Ferede, Y. | Mazengia, H. | Tilahun, M.
The objective was to evaluate the growth and reproductive performances of Fogera cattle breed at Andassa Livestock Research Center, Ethiopia. The data covers the period from 1992 to 2013 that were collected from farm records of the center. The fixed effects were birth year, season, sex, parity, mating type and dam source. The least squares means and standard errors of birth and weaning weight were 21.4±0.09 and 102±0.77 kg, respectively; whereas age at first service, age at first calving, calving interval and number of service per consumption were 38.9±0.72 month, 51.8±0.72 month, 19.5±0.32 month and 1.17±0.01, respectively. Weaning weight and other reproductive performance traits showed slight up and down trends across the years which indicated fluctuation of management and other husbandry practices at the center. Almost all the non-genetic factors considered in the study had an effect on the production and reproductive performances of the breed.
Mostrar más [+] Menos [-]Recording birth weight has no significance in village based genetic improvement programs of small ruminants Texto completo
2016
Jembere, T. | Kebede, K. | Rischkowsky, Barbara A. | Haile, Aynalem | Okeyo Mwai, Ally | Dessie, Tadelle
Community based sheep breeding programs: Tapping into indigenous knowledge Texto completo
2013
Haile, Aynalem | Mirkena, Tadele | Duguma, Gemeda | Wurzinger, Maria | Rischkowsky, Barbara | Tibbo, Markos | Mwai, Ally Okeyo | Sölkner, Johann
A study was undertaken to understand local knowledge and practices of communities in animal management as a step in designing and implementation of communitybased breeding programs for four local breeds (Afar, Bonga, Horro and Menz) in four sites in Ethiopia. Workshops were held with the project communities to learn their animal management practices, among others the selection of rams and ewes, ram sharing and grazing management. Breeding management skills were studied by conducting heritability and genetic correlation exercises. The most important animal traits for the different production systems were identified from a systems study. Phenotypic, production, and reproduction traits were used either in the form of drawings or verbal explanations. Pairwise combinations of the traits were presented to the communities to express their choices via voting. For evaluating heritability, the communities were asked which trait pair is relatively more heritable than the other. For the correlation exercise, the communities were asked to estimate the magnitude (high, low, and none) of relationship between the traits in each pair. The results indicate that farmers and pastoralists have good skills in sheep management. Although the mating system is generally uncontrolled, the farmers have a tradition of exchanging of rams. All farmers/pastoralists exercise ewe and ram selection based on phenotypic appearance and recalled pedigree. Their knowledge on heritability of traits and genetic correlations between traits more or less concurs with scientific evidence in literature. For example, qualitative traits (like colour) were judged highly heritable followed by production traits. Knowledge of correlations is used for indirect selection when the target traits are either impossible to assess on the live animal or are sexlimited. Indigenous knowledge and existing practices in the communities, developed through years of practical experience, provide an excellent basis for designing sheep breeding programs.
Mostrar más [+] Menos [-]Open geo-spatial data for sustainable forest management: Lithuanian case Texto completo
2020
Tiskute-Memgaudiene, D., Vytautas Magnus Univ., Kaunas (Lithuania) | Mozgeris, G., Vytautas Magnus Univ., Kaunas (Lithuania) | Gaizutis, A., Forest Owners Association of Lithuania, Vilnius (Lithuania);Vilnius University (Lithuania)
In Lithuania, forests are managed by Lithuanian State Forest Enterprise, municipalities, ministries, etc. and private forest owners. About 50% of all forest land is State importance, privately owned forests cover 40% of forest land, and about 10% of forest land belongs to forests reserved for restitution. Forest management of private ownership force many challenges, because private forest owners are people, who have purchased or received the property after restitution, and often lacks knowledge about forest resources, its dynamics and sustainable forest management. As remote sensing is a valuable source for forest monitoring, because it provides periodic data on forest resource and condition status, these methods are gaining increased attention worldwide. In this context, more scientific efforts are made at developing remote sensing derived geo-spatial data services for sustainable forest management through a web service platform, which would integrate geo-information into daily decision making processes and operation for private forest owners. This article presents a review of privately owned forests’ statistics, questionnaire-based survey about GIS usage and demand for forest owners in Lithuania and links available sources of open geo-spatial data useful for sustainable forest management.
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